Cyclodextrin complexes medium influences

D. Reaction Cavities with Strong External Medium Influences Cyclodextrin Complexes and Their Aqueous Solutions... 

Others have investigated the influence of the presence of (i-cyclodextrin in the reaction medium on the electrochemical carboxylation of a-bromoethylbenzene and l-(4-isobutylphenyl)ethyl chloride [41], It has been reported that the preparative electrocarboxylahon of the inclusion complex (i-cyclodextrin-l-(4-isobutylphenyl) ethylchloride afforded the S-form of 2-(4-isobutylphenyl) propionic acid (S-ibuprofen) in a high enantiomeric excess (97%). 

The cause of the scatter is the non-systematic influence of the substituent on the microscopic environment of the transition structure. The linear free energy relationship between product state XpyH (Equation 22) and the transition structure (Xpy. .. PO32 . . . isq) will be modulated by second-order non-systematic variation because the microscopic environment of the reaction centre in the standard (XpyH ) differs slightly from that (Xpy-PO ) in the reaction under investigation giving rise to specific substituent effects. These effects are mostly small. An unusually dramatic intervention of the microscopic medium effect may be found in Myron Bender s extremely scattered Hammett dependence of the reaction of cyclodextrins with substituted phenyl acetates.22 The cyclodextrin reagent complexes the substrate and interacts... 

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